// Functions used by iterators -*- C++ -*-
// Copyright (C) 2001, 2002 Free Software Foundation, Inc.
//
// This file is part of the GNU ISO C++ Library. This library is free
// software; you can redistribute it and/or modify it under the
// terms of the GNU General Public License as published by the
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// any later version.
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
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// Software Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307,
// USA.
// As a special exception, you may use this file as part of a free software
// library without restriction. Specifically, if other files instantiate
// templates or use macros or inline functions from this file, or you compile
// this file and link it with other files to produce an executable, this
// file does not by itself cause the resulting executable to be covered by
// the GNU General Public License. This exception does not however
// invalidate any other reasons why the executable file might be covered by
// the GNU General Public License.
/*
*
* Copyright (c) 1994
* Hewlett-Packard Company
*
* Permission to use, copy, modify, distribute and sell this software
* and its documentation for any purpose is hereby granted without fee,
* provided that the above copyright notice appear in all copies and
* that both that copyright notice and this permission notice appear
* in supporting documentation. Hewlett-Packard Company makes no
* representations about the suitability of this software for any
* purpose. It is provided "as is" without express or implied warranty.
*
*
* Copyright (c) 1996-1998
* Silicon Graphics Computer Systems, Inc.
*
* Permission to use, copy, modify, distribute and sell this software
* and its documentation for any purpose is hereby granted without fee,
* provided that the above copyright notice appear in all copies and
* that both that copyright notice and this permission notice appear
* in supporting documentation. Silicon Graphics makes no
* representations about the suitability of this software for any
* purpose. It is provided "as is" without express or implied warranty.
*/
/** @file stl_iterator_base_funcs.h
* This is an internal header file, included by other library headers.
* You should not attempt to use it directly.
*
* This file contains all of the general iterator-related utility
* functions, such as distance() and advance().
*/
#ifndef __GLIBCPP_INTERNAL_ITERATOR_BASE_FUNCS_H
#define __GLIBCPP_INTERNAL_ITERATOR_BASE_FUNCS_H
#pragma GCC system_header
#include
namespace std
{
template
inline typename iterator_traits::difference_type
__distance(_InputIterator __first, _InputIterator __last,
input_iterator_tag)
{
// concept requirements
__glibcpp_function_requires(_InputIteratorConcept)
typename iterator_traits::difference_type __n = 0;
while (__first != __last) {
++__first; ++__n;
}
return __n;
}
template
inline typename iterator_traits::difference_type
__distance(_RandomAccessIterator __first, _RandomAccessIterator __last,
random_access_iterator_tag)
{
// concept requirements
__glibcpp_function_requires(_RandomAccessIteratorConcept)
return __last - __first;
}
/**
* @brief A generalization of pointer arithmetic.
* @param first An input iterator.
* @param last An input iterator.
* @return The distance between them.
*
* Returns @c n such that first + n == last. This requires that @p last
* must be reachable from @p first. Note that @c n may be negative.
*
* For random access iterators, this uses their @c + and @c - operations
* and are constant time. For other %iterator classes they are linear time.
*/
template
inline typename iterator_traits::difference_type
distance(_InputIterator __first, _InputIterator __last)
{
// concept requirements -- taken care of in __distance
return __distance(__first, __last, __iterator_category(__first));
}
template
inline void
__advance(_InputIter& __i, _Distance __n, input_iterator_tag)
{
// concept requirements
__glibcpp_function_requires(_InputIteratorConcept)
while (__n--) ++__i;
}
template
inline void
__advance(_BidirectionalIterator& __i, _Distance __n,
bidirectional_iterator_tag)
{
// concept requirements
__glibcpp_function_requires(_BidirectionalIteratorConcept)
if (__n > 0)
while (__n--) ++__i;
else
while (__n++) --__i;
}
template
inline void
__advance(_RandomAccessIterator& __i, _Distance __n,
random_access_iterator_tag)
{
// concept requirements
__glibcpp_function_requires(_RandomAccessIteratorConcept)
__i += __n;
}
/**
* @brief A generalization of pointer arithmetic.
* @param i An input iterator.
* @param n The "delta" by which to change @p i.
* @return Nothing.
*
* This increments @p i by @p n. For bidirectional and random access
* iterators, @p n may be negative, in which case @p i is decremented.
*
* For random access iterators, this uses their @c + and @c - operations
* and are constant time. For other %iterator classes they are linear time.
*/
template
inline void
advance(_InputIterator& __i, _Distance __n)
{
// concept requirements -- taken care of in __advance
__advance(__i, __n, __iterator_category(__i));
}
} // namespace std
#endif /* __GLIBCPP_INTERNAL_ITERATOR_BASE_FUNCS_H */